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© 2003 American Society for Clinical Oncology Perceptions of Patients and Physicians Regarding Phase I Cancer Clinical Trials: Implications for Physician-Patient Communication
From the Divisions of Medical Science and Population Science, Fox Chase Cancer Center, Philadelphia, PA; Duke University, Durham, NC; Georgetown University, Washington, DC; Northwestern University, Chicago, IL; University of Maryland, Baltimore, and National Cancer Institute Office of Cancer Survivorship, Bethesda, MD; and St Vincent Catholic Medical Centers, New York, NY. Address reprint requests to Neal J. Meropol, MD, Fox Chase Cancer Center, 7701 Burholme Ave, Philadelphia, PA 19111; email: nj_meropol{at}fccc.edu.
Purpose: To describe and compare the perceptions of cancer patients and their physicians regarding phase I clinical trials. Methods: Eligible patients had been offered phase I trial participation and had decided to participate but had not yet begun treatment. Each patient’s physician also served as a study subject. Patients and physicians completed questionnaires with domains including perceptions of potential benefit and harm from treatment (experimental and standard), relative value of quality and length of life, and perceived content of patient-physician consultations. Results: Three hundred twenty-eight patients and 48 physicians completed surveys. Patients had high expectations regarding treatment outcomes (eg, median 60% benefit from experimental therapy), with those choosing to participate in a phase I trial being more optimistic than those declining phase I participation. Patients predicted a higher likelihood of both benefit and adverse reactions from treatment (experimental and standard) than their physicians (P < .0001 for all comparisons). Although 95% of patients reported that quality of life was at least as important as length of life, only 28% reported that changes in quality of life with treatment were discussed with their physicians. In contrast, 73% of physicians reported that this topic was discussed (P < .0001). Conclusion: Cancer patients offered phase I trial participation have expectations for treatment benefit that exceed those of their physicians. The discordant perceptions of patients and physicians may possibly be explained by patient optimism and confidence; however, the discrepancies in reports of consultation content, particularly given patients’ stated values regarding quality of life, raise the possibility that communication in this context is suboptimal.
THE CLINICAL development of improved systemic therapies for cancer generally begins with phase I studies in subjects with metastatic disease for whom standard approaches have either failed, have low expectation of benefit, or do not exist. The primary objectives of most phase I studies are to determine the toxicity profile of a new agent (or new combination) and the maximum-tolerated dose. Phase I trials of recently developed targeted agents may include identification of a minimum biologically active dose as a primary end point. These objectives govern study design, which involves treatment of small cohorts of patients with escalating drug doses. Although introduction of new therapies into the clinic is based on demonstrated activity in cell culture and animal models, historically, less than 5% of patients who enroll in phase I trials have benefited from participation.1,2 Patients offered treatment on phase I trials are vulnerable given their generally poor short-term prognoses and the lack of encouraging standard treatment options. This vulnerability, coupled with uncertainty regarding potential benefits and toxicities of experimental therapy, creates a unique and difficult medical decision-making context. We3,4 and others5,6 have sought to describe the perceptions of cancer patients who are considering participation in phase I clinical trials. Results of these pilot studies suggest that patients have high expectations regarding the benefit of experimental therapy and participate largely in the hope of achieving medical benefit, with altruism playing only a minor role.3–5 In addition, patients had higher expectations of benefit than their physicians, despite having completed the informed-consent process.3 In a survey of 30 patients choosing to participate in phase I trials, we observed a wide range of expectations regarding treatment outcomes.3 Expectations regarding benefit of experimental therapy were correlated both with expectations regarding benefit of standard therapy and general health perceptions; these findings suggested that even among patients who have consented to participate in a phase I trial, there is not a uniform decision-making calculus. In an effort to further explore models of decision making for patients considering participation in phase I clinical trials, we undertook a large-scale, multicenter study of patients considering phase I study participation and their physicians. Our study hypotheses addressed issues ranging from expectations of the patients to more formal models of decision-making by patients in terms of weighing risks and benefits of therapy. In this article, we present the study results regarding patient expectations and patient-physician communication. Our initial hypothesis was that patients would have high expectations about the potential for benefit from phase I trials, with those patients choosing to take part in an investigational treatment (acceptors) being more optimistic about both risks and benefits than those declining participation (decliners). In addition, on the basis of our pilot experience,3 we hypothesized that patients would have higher expectations for benefit than their physicians. In a preliminary effort to describe aspects of physician-patient communication that might impact patient perceptions and decision making, we queried patients and physicians about the content of their consultations.
Study Subjects Eligible subjects were adult cancer patients at four United States academic oncology centers who had been offered participation in phase I studies and had made the decision of whether to participate. Patients offered participation in phase I trials included both those individuals who had discussions with their physicians about specific phase I clinical trials, and those individuals who had discussions with their physicians about phase I trials in general, but did not necessarily discuss specific studies. Patients who had already initiated treatment were excluded. Eligibility criteria included the following: Advanced malignancy for which there is either no standard effective therapy or for which standard therapy has previously failed; 18 years of age or older; life expectancy of at least 3 months; and performance status of 0 to 2 (ie, the patient is ambulatory at least 50% of the time). Attending physicians responsible for the patients enrolled in this study also served as study subjects. Potential patient subjects were identified by several methods, including physician contact, nurse contact, protocol office logs, and phase I team meetings at individual clinical sites. Completeness of ascertainment of those subjects choosing to participate in a phase I study was confirmed by comparison with protocol office enrollment lists. Physician consent was obtained before patient contact. Written patient consent to participate as a study subject was then obtained. Patient baseline surveys were conducted either in person or by phone. Once patient consent was obtained, the attending physician (medical oncologist) involved in the decision regarding phase I study participation consented to serve as a study subject and was given a written survey to complete within 3 days. The study design and survey instruments were approved by the institutional review boards at each participating study site (Fox Chase Cancer Center, Philadelphia, PA; University of Maryland, Baltimore, MD; Georgetown University, Washington, DC; Northwestern University, Chicago, IL; and Duke University, Durham, NC [Data Management Center]).
Questionnaires Physician questionnaires were given to the attending oncologist of each patient participating in this study. The questionnaire consisted of two sections. Section I obtained the physician’s demographic information, educational background, and phase I clinical trial experience. This section was only completed once annually. Section II obtained physician perceptions of benefits, toxicities, and predicted survival from experimental and standard therapies. Information on the patient’s cancer history, treatment options offered, issues discussed with the patient, and perceived issues of importance to the patient in deriving a treatment choice was also gathered. Section II was administered individually for each patient, and this survey took place before treatment was initiated.
Measures Potential benefit and harm. To measure both patients’ and physicians’ expectations of experimental or standard treatments, we asked respondents to place a mark on horizontal bars ranging from 0% to 100% to describe the likelihood of health outcomes (benefit, ie, the probability that a treatment would "control your cancer" [patients] or "benefit your patient" [physicians], and harm, ie, the probability that a treatment would cause a "severe adverse reaction" [patients and physicians]) associated with the different treatments. Patients were asked to estimate their life expectancy with experimental or standard therapy by selecting from among nine choices, ranging from less than 1 month to more than 8 years. Patients were asked to indicate the maximum benefit they thought a patient with their type and stage of cancer might experience as a result of standard or experimental therapy. The five responses to this question included "will not shrink cancer or improve symptoms," "will not shrink cancer, but will improve symptoms," "cancer is controlled (ie, will not get any worse, stable disease)," "reduction in the number or size of tumors," and "cancer totally cured." To assess overall patient confidence in a favorable outcome, we presented patients with a hypothetical scenario that described a new treatment for cancer that benefits 20 of 100 patients. Patients were asked to rate their confidence that they would be one of the patients who would benefit from the treatment. Five choices included "definitely will be one of the 20," "may be one of the 20," "unsure," "may not be one of the 20," and "definitely will not be one of the 20." Quality and length of life. A five-item Likert-type scale was used to determine the extent to which patients valued quality of life versus length of life, with choices including "quality of life is all that matters," "quality of life is more important," "both are equally important," "length of life is more important," and "length of life is all that matters." Content of consultations. To determine the level of agreement between patients and their physicians on what issues were discussed during their consultations, we asked patients whether anyone discussed each of seven topics relating to changes in quality or length of life as a result of therapy. When patients indicated that someone had discussed an issue, they then indicated who (nurse, physician, or other) had talked to them about each issue. Physicians were asked whether they had discussed each of the same seven items with the patient.
Statistical Considerations Given that many patients had difficulty answering the questions regarding life expectancy, we analyzed responses to these questions in two ways. First, we created a new variable that indicated whether the patient provided a response regarding life expectancy (from among the nine choices) or not. The nonresponse category included patients with missing data, or a response of "Not applicable," "Refused," or "Don’t know/Unsure." We then compared the percentage of patients among acceptors and decliners who were able to provide an estimate of life expectancy. Second, of those who provided an estimate of life expectancy, we compared the distributions of acceptors and decliners using a Wilcoxon rank sum test. Differences between patients’ and physicians’ expectations regarding the benefit and harm from experimental and standard therapies were computed for the total sample and for acceptors and decliners separately. Wilcoxon signed-rank tests were used to determine whether the median difference score was different from zero. Acceptors and decliners were compared using a Wilcoxon rank sum test. Differences between patients’ and physicians’ reports of what trial-related information was communicated were tested using McNemar’s test for correlated proportions. To examine the extent of bias created by missing data, we selected two different instances of missing data. Patients who did not answer all four variables concerning the chance of benefit or harm from experimental and standard therapies were compared with patients who did answer these variables with respect to age, sex, race, marital status, education, and tumor type. Patients who did or did not have a completed physician survey were compared also with respect to the patient characteristics just listed. The highly nonnormal distributions of responses required the use of nonparametric tests, for which adjustments owing to clustering within physician are not possible. For purposes of sensitivity analyses, however, we reanalyzed the data using generalized estimating equation models with different link functions (identity, log-link, and so on) both with and without adjustments for clustering by physician. This was possible for all analyses except for the Mantal-Haenzel comparisons between acceptors and decliners and the McNemar’s tests comparing patients and physicians with respect to consultation content. Adjustment for clustering did not affect whether a finding was considered significant (< .05), except in one case, which is indicated in Results. All study analyses were conducted separately by clinical site. The direction of all differences was consistent across sites, and thus we present only data pooled across the four sites.
Patient Characteristics A total of 593 patients were offered enrollment in this study, and 328 (55%) participated (184 men and 144 women). A total of 260 (79%) of these subjects chose to enroll in a phase I trial. Three months after enrollment, there was no difference in death rates between those patients who chose to participate in a phase I trial and those who decided not to participate.
Patient characteristics are listed in Table 1
Patient Expectations Regarding Treatment Outcomes Table 2  shows patient expectations (on the scale from 0% to 100%) regarding whether experimental and standard therapies would control their cancer or result in a severe adverse reaction. Seventy-seven percent of patients estimated that their chance of benefit from experimental therapy was at least 50%. Patients who chose to participate in a phase I trial reported a greater chance that they would benefit from experimental therapy compared with patients who declined to participate (P < .0001). Half of the acceptors estimated a chance of benefit of at least 70%. Decliners, on the other hand, reported higher expectations of benefit from standard treatment than did patients who elected to participate in a phase I trial (P < .01). Acceptors also perceived a significantly lower chance of experiencing a serious adverse event with an experimental therapy than did patients who declined to participate (P < .001). There were no differences between decliners and acceptors in the perceived chance of a serious adverse event as a result of standard therapy.
Survey items also explored patient perceptions regarding the maximum benefit that could be attained with experimental therapy and the level of confidence that patients had regarding personal benefit. As shown in Table 3 , perception of maximum benefit differed significantly (P = .03) between acceptors and decliners, with more acceptors than decliners believing that cancer could be totally cured by the phase I treatment. In addition, patients who agreed to participate in phase I trials were more confident that they would benefit from a new hypothetical treatment for cancer, compared with patients who declined to participate.
In response to the question about their life expectancy if they received an experimental therapy, more phase I acceptors (70%) were able to provide an estimate than decliners (44%; P < .0005). Figure 1A shows the distribution of responses separately by decliners and acceptors. Although the number of patients for any given response category was small, several relationships were apparent. For those patients who were able to provide an estimate of life expectancy, acceptors reported longer life expectancy with experimental therapy than did decliners (P < .0005). In response to the same question about their life expectancy if they received standard therapy, phase I decliners (62%) were just as likely to provide an estimate as acceptors (62%). Figure 1B shows the distribution of responses separately by decliners and acceptors. For those patients who were able to provide an estimate of life expectancy, there were no differences between acceptors and decliners (P = .99). Overall, 71% of subjects believed they would live 2 or more years with experimental therapy, and 45% felt they would live 2 or more years with standard therapy.
Comparisons Between Patient and Physician Perceptions The mean age of the physician sample (n = 48) was 43.8 years (age only available for 45 subjects), with 26% female and 74% male. Physicians’ expectations concerning their patients’ chances of experiencing benefit or serious adverse event are shown in Table 4 . Physician expectations were similar for acceptors and decliners. Compared with the patients’ expectations summarized in Table 2 , physician expectations were lower in both central tendency and the maximum values given for both potential benefit and toxicity of standard and experimental therapies, regardless of whether the patients were acceptors or decliners. Table 4 shows the distribution of difference scores between patients and their physicians (difference = patient - physician). Regardless of whether the patients accepted or declined phase I treatment, patients tended to provide higher ratings of the chances of both benefit and adverse events for both types of treatment (ie, median difference scores for all four expectation variables were positive and significantly different from zero; P < .0001). The discrepancy between patients and their physicians, however, was significantly greater among acceptors (median = 40) than decliners (median = 10) regarding expectations of benefit with experimental treatment. Thus although both acceptors and decliners tended to report higher chances of benefit than their physicians, acceptors’ reports were especially discrepant relative to decliners.
Table 5 lists the perceptions of patients and their physicians concerning what treatment-related information was discussed during their consultations. For all issues, there was significant discordance between patients and physicians about whether the issue had been discussed, with physicians more likely to report that each item was discussed. The greatest discordance was observed for discussion of changes in quality of life with treatment. With regard to patient valuation of quality versus length of life, only 5% of subjects responded that length of life was more important ("length of life is all that matters" or "length of life is more important") than quality of life on a five-point scale.
Bias as a Result of Missing Data Patients who had missing data for any one of the four expectation questions (control cancer/standard, control cancer/experimental, severe adverse reaction/standard, severe adverse reaction/experimental) regarding treatment variables did not differ from those with complete data on age, sex, race, marital status, education, or tumor type. Patients for whom complete physician data (on expectation regarding treatment item) were available were similar to other patients in terms of age, sex, race, marital status, and education. Patients with the more common diagnoses of breast, lung, colon, or pancreas cancer were less likely to have physicians with missing expectation data than patients with other cancer types (P = .001).
This multicenter study was conducted to characterize the perceptions of advanced cancer patients who had considered participation in a phase I trial and compare these perceptions to those of their physicians. In contrast to almost all previous studies of cancer patient decision-making, the current study included patients who declined protocol enrollment as well as those who accepted participation in a treatment clinical trial. The findings presented demonstrate significant differences in the expectations of patients choosing to participate in a phase I trial compared with those of patients who declined participation. In addition, there was significant discordance between the perceptions of patients and their attending physicians regarding treatment outcomes and the content of their consultations. Consistent with previous reports,3,5we found that patients were relatively optimistic regarding their treatment outcomes, regardless of whether they chose an experimental or standard treatment. This finding was consistent across various measures, including the perceived chance of benefit, life expectancy, maximum benefit, and confidence. For example, three quarters of the sample reported that their chance of benefit from an experimental treatment was greater than 50%. Overall, more than two thirds of the patients felt they would live 2 or more years with experimental treatment, and close to half felt they would live 2 or more years with standard therapy. These findings are notable given that, in general, patients offered phase I trials have refractory malignancies with life expectancy measured in months.14 Patients who agreed to participate in a phase I study had greater perceived chance of benefit, anticipated living longer and experiencing a greater maximum potential benefit, and had greater confidence in a favorable outcome with experimental treatment than patients who declined to participate. These findings are generally supportive of most models of decision making that predict that patients will favor treatments with greater perceived potential benefit and lower perceived risk.15–17 In our recently developed Health Stock Risk Adjustment Model,16 we postulate that patients facing life-threatening illnesses, such as those in the current study, will weight potential benefits and also discount the risks associated with treatment. The concept of health stock is defined as an individual’s prediction of future quality-adjusted life expectancy.18 In the Health Stock Risk Adjustment model, we postulate that relative health stock is a key determinant of treatment choice. Relative health stock represents a ratio between current health stock and one’s health stock before the current diagnosis or change in clinical status. Thus two individuals with a recent diagnosis of pancreas cancer may have similarly low health stock, but their relative health stock may differ dramatically based on their prediagnosis age, comorbidities, quality of life, and so on (ie, an individual with longstanding comorbidities would have higher relative health stock after receiving a new diagnosis of pancreas cancer than an individual who was previously healthy when given this diagnosis). We postulate that as relative health stock decreases, patients adopt a more risk-accepting decision-making calculus, tending to discount toxicity and overweight potential benefits in arriving at a treatment valuation. The fact that the acceptors in our study predicted a high likelihood of significant side effects (median 30%) and also predicted a greater likelihood of side effects than their physicians is consistent with this hypothesis. We found significant differences between patients and their physicians for expectations of both benefit and harm associated with both experimental and standard therapies. One explanation for this finding is that patient communication of probability information may be different than that of physicians. For example, when we asked patients whether they would benefit from a treatment that offers a 20% chance of cure, 44% of patients reported they would be among those who would benefit. Thus patients may be communicating their confidence in their individual treatment outcomes rather than the relative frequency of a response in a population. It is also plausible that the manner in which benefit and risk information was assessed for patients and physicians contributed to our findings of discordance. For patients, the benefit item was phrased as an expectation that treatment would "control your cancer" (0% to 100%), whereas the physician item asked about the expectation that treatment would "benefit the patient" (0% to 100%). Regarding this item, one might have expected positive skewing of the physician responses (resulting in a minimization of patient-physician discordance) because "benefit" may be interpreted as a broader term than "control cancer." With regard to assessment of risk, both patients and physicians were asked to consider the potential for a "severe adverse reaction" (0% to 100%). For clarification, patients were also prompted with the phrase "negative effects of therapy." The impact of this additional language on our study results is uncertain but could have conceivably led patients to include less severe side effects than their physicians in their outcome estimations. Another possible explanation for our findings regarding treatment outcome expectations is that the differences between patients and physicians result from a failure of patient-physician communication. Several other studies comparing the perceptions of patients and their physicians have been reported. In general, advanced cancer patients have higher estimates for a favorable outcome (eg, survival, tumor response) than their physicians.19–22 Patients and physicians also have discordant perceptions about decision-making preferences regarding cancer treatment and end-of life decisions.23–27 These previous observations and those presented here raise the possibility that in many contexts, in particular those involving life-threatening illness, physician-patient communication is suboptimal. This may be of particular bioethical concern, given the common preference of cancer patients for a shared decision-making model.23 The current study did not provide direct measurement of patient-physician communication. However, when asked identical questions regarding the content of their consultations, the patients and physicians in our survey had discordant perceptions. Furthermore, the greatest discordance was found regarding discussions of quality of life. Less than one third of patients reported that impact of treatment on quality of life was discussed, whereas approximately two thirds of their physicians reported discussion of this issue. Because nearly all patients in the current study rated quality of life at least as important as length of life, this finding raises the possibility that issues most relevant to patient values are not being optimally addressed by providers. It is also conceivable that physicians define quality of life differently than patients and that this may lead to a disconnect in the physician-patient dialogue. Such conclusions will require further study that includes direct observation of patient-physician communication, exploration of the meaning to patients and providers of commonly used language (eg, quality of life), and careful measurement of patient satisfaction with consultations. The data presented have several potential limitations. Nonresponse bias may exist, given that many patients offered phase I trials chose not to enroll in this survey study. Because patients declining phase I trial participation may obtain their ongoing oncologic care outside of the academic centers participating in this study, it is likely that the participation rate of phase I acceptors was higher than that of decliners in our study. We included study participants with a wide variety of malignancies from four clinical centers in an effort to reduce bias related to underlying disease and health care delivery system differences. Selection bias in patient ascertainment is another theoretical concern. We recognized this potential bias in designing the study and undertook special efforts to identify and enroll all eligible subjects, including extensive training of study site personnel, systems analyses at each participating site to achieve maximal patient ascertainment, and concerted efforts to enroll patients who declined phase I participation. Effective standard treatment options for patients with advanced solid tumors are limited, and therefore participation of patients in early-phase clinical trials is of great importance in ultimately improving clinical outcome. The decision-making context for patients considering phase I trials is particularly complex and difficult given that patients are facing mortality, there is uncertain and historically low potential for individual benefit, and there is uncertain and significant potential for side effects. The data presented suggest significant discordance between patients and providers regarding perceived risks and benefits of therapy. The high expectations for treatment benefit reflected in patient responses may in part reflect optimism and confidence rather than incomplete understanding of outcome probabilities. Future survey research should address these distinctions. However, the divergent responses of patients and physicians regarding consultation content raise the possibility that patient-provider communication is incomplete concerning issues of great importance in decision-making. Direct observation of patient-physician communication with careful analysis of recorded encounters will be required to fully characterize this issue. In summary, further exploration of the decision making of patients with advanced cancer and the communication between patients and physicians can help determine the extent to which our findings indicate a bioethical concern regarding the informed consent process.
Participating sites, investigators, and study coordinators are as follows: Fox Chase Cancer Center, Philadelphia, PA (principal investigator, Neal J. Meropol, MD; study coordinators, Joanne Buzaglo, PhD; Sandra Corbett, MS; and Jennifer Driscoll, MS); Georgetown University, Washington, DC (principal investigator, Caroline B. Burnett, ScD, RN; study coordinator, Shakira Washington, MHA); Lurie Cancer Center, Northwestern University, Chicago, IL (principal investigator, Al B. Benson, III, MD; study coordinator, Kimberly Smith, MS); University of Maryland, Baltimore, MD (principal investigator, David Van Echo, MD; study coordinator, Jennifer DeSanto, RN, MS); Duke University Medical Center, Durham, NC (principal investigator, Kevin A. Schulman, MD; study coordinator, Liana D. Castel, MSPH).
Supported by National Cancer Institute grant no. R01 CA82085 (N.J.M.). Presented in part at the Thirty-Eighth Annual Meeting of the American Society of Clinical Oncology, May 18–21, 2002, Orlando, FL.
1. Smith TL, Lee JJ, Kantarjian HM, et al: Design and results of phase I cancer clinical trials: Three-year experience at M.D. Anderson Cancer Center. J Clin Oncol 14:287–295, 1996[Abstract] 2. Von Hoff DD, Turner J: Response rates, duration of response, and dose response effects in phase I studies of antineoplastics. Invest New Drugs 9:115–122, 1991[Medline]
3. Cheng JD, Hitt J, Koczwara B, et al: Impact of quality of life on patient expectations regarding phase I clinical trials. J Clin Oncol 18:421–428, 2000 4. Schutta KM, Burnett CB: Factors that influence a patient’s decision to participate in a phase I cancer clinical trial. Oncol Nurs Forum 27:1435–1438, 2000[Medline] 5. Daugherty C, Ratain MJ, Grochowski E, et al: Perceptions of cancer patients and their physicians involved in phase I trials. J Clin Oncol 13:1062–1072, 1995[Abstract]
6. Daugherty CK: Impact of therapeutic research on informed consent and the ethics of clinical trials: A medical oncology perspective. J Clin Oncol 17:1601–1617, 1999 7. Degner LF, Sloan JA, Venkatesh P: The control preferences scale. Can J Nurs Res 29:21–43, 1997[Medline]
8. O’Connor AM: Validation of a decisional conflict scale. Med Decis Making 15:25–30, 1995 9. Ware J Jr, Kosinski M, Keller SD: A 12-item short-form health survey: Construction of scales and preliminary tests of reliability and validity. Med Care 34:220–233, 1996[CrossRef][Medline] 10. Euroqol G: EuroQol: A new facility for the measurement of health-related quality of life—The EuroQol Group. Health Policy 16:199–208, 1990[CrossRef][Medline] 11. Mandelblatt JS, Hadley J, Kerner JF, et al: Patterns of breast carcinoma treatment in older women: Patient preference and clinical and physical influences. Cancer 89:561–573, 2000[CrossRef][Medline] 12. Mandelblatt JS, Berg CD, Meropol NJ, et al: Measuring and predicting surgeons’ practice styles for breast cancer treatment in older women. Med Care 39:228–242, 2001[CrossRef][Medline] 13. Mandelblatt JS, Bierman AS, Gold K, et al: Constructs of burden of illness in older breast cancer patients: A comparison of measurement methods. Health Serv Res 36:1085–1107, 2001[Medline]
14. Bachelot T, Ray-Coquard I, Catimel G, et al: Multivariable analysis of prognostic factors for toxicity and survival for patients enrolled in phase I clinical trials. Ann Oncol 11:151–156, 2000
15. Verhoef LCG, DeHaan AFJ, Van Daal WAJ: Risk attitude in gambles with years of life: Empirical support for prospect theory. Med Decis Making 14:194–200, 1994
16. Gaskin DJ, Kong J, Meropol NJ, et al: Treatment choices by seriously ill patients: The Health Stock Risk Adjustment model. Med Decis Making 18:84–94, 1998 17. Weinstein ND: Testing four competing theories of health-protective behavior. Health Psychol 12:324–333, 1993[CrossRef][Medline] 18. Grossman M: On the concept of health capital and the demand for health. J Pol Econ 80:223–255, 1972[CrossRef]
19. Weeks JC, Cook EF, O’Day SJ, et al: Relationship between cancer patients’ predictions of prognosis and their treatment preferences. JAMA 279:1709–1714, 1998 20. Varma G, Stein R, Jacobson J, et al: The goal of chemotherapy: Little agreement between patients and their doctors. Proc Am Soc Clin Oncol 20:386a, 2001 (abstr 1542)
21. Lee SJ, Fairclough D, Antin JH, et al: Discrepancies between patient and physician estimates for the success of stem cell transplantation. JAMA 285:1034–1038, 2001 22. Quirt CF, Mackillop WJ, Ginsburg AD, et al: Do doctors know when their patients don’t? A survey of doctor-patient communication in lung cancer. Lung Cancer 18:1–20, 1997[CrossRef][Medline]
23. Bruera E, Sweeney C, Calder K, et al: Patient preferences versus physician perceptions of treatment decisions in cancer care. J Clin Oncol 19:2883–2885, 2001 24. Rothenbacher D, Lutz MP, Porzsolt F: Treatment decisions in palliative cancer care: Patients’ preferences for involvement and doctors’ knowledge about it. Eur J Cancer 33:1184–1189, 1997[CrossRef][Medline] 25. Fischer GS, Tulsky JA, Rose MR, et al: Patient knowledge and physician predictions of treatment preferences after discussion of advanced directives. J Gen Intern Med 13:447–454, 1998[CrossRef][Medline] 26. Haidet P, Hamel MB, Davis RB, et al: Outcomes, preferences for resuscitation, and physician-patient communication among patients with metastatic colorectal cancer: SUPPORT Investigators Study to understand prognoses and preferences for outcomes and risks of treatments. Am J Med 105:222–229, 1998[CrossRef][Medline]
27. Sulmasy DP, Dwyer M, Marx E: Do the ward notes reflect the quality of end-of-life care? J Med Ethics 22:344–348, 1996 Submitted October 15, 2002; accepted April 15, 2003.
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Copyright © 2003 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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ABSTRACT
INTRODUCTION
2 and Fisher’s exact test for nominal categorical variables, Wilcoxon rank sum test for nonnormally distributed continuous variables or ordinal categorical variables, and t test for continuous variables that were approximately normally distributed. 
